Re: (ET) [Fwd: Re: charger problem]

["David Roden" <etpost drmm net>]

Trying to determine when the battery is charged by voltage alone is like 
trying to figure out whether you've arrived at your destination by mileage 
alone -- it helps to know which direction you've been driving, too!

A battery is charged when it reaches an on-charge voltage of 2.4 to 2.5 
volts per cell (different manufacturers give different numbers), ideally 
adjusted for temperature, AND the current at that voltage has fallen to 
0.05C (2% of the battery's 20 hour amp-hour capacity expressed in amperes).

An alternate scheme is called dv/dt, meaning the derivative of voltage 
with 
respect to time and referring to the slope of the voltage rise while 
charging. This algorithm samples the voltage periodically and when it has 
stopped rising, is rising very slowly, or (especially) has started to 
decline, calls the job done.

If I were using golf car batteries and the GE charger, I would want to see 
about 44 volts with the charger operating, and a charging current of under 
5 
amps.  Then I'd say "charged."